Enzymarchitektur der Niere and Sexualhormone

Sexual difference and organ specificity of the effect of estradiol on carbonic anhydrase and Mg(2+)-HCO3(-)-ATPase activities isolated from duodenal mucosa and kidney cortex of male and female rats: preliminary study with crude enzyme samples

Effects of the s.c. administration of various doses of estradiol propionate (E.P.; 25-500 micrograms/kg) on the activities of carbonic anhydrase (CA), Mg(2+)-dependent ATPase and Mg(2+)-dependent, HCO3(-)-stimulated ATPase (Mg(2+)-HCO3(-)-ATPase) in rat duodenal mucosa and kidney cortex, and on body weight, organ weight and serum concentrations of testosterone and estradiol-17 beta, were examined in adult male, female, testectomized and ovariectomized rats. In normal male rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the kidney were increased in a dose-dependent manner and reached 1.6- and 2-fold of controls, respectively, after consecutive administration (daily for 7 days) of 500 micrograms E.P. with no changes in either enzyme activities in duodenal mucosa. The positive correlations (P less than 0.01) were observed by linear regression analysis between serum concentration of estradiol-17 beta and kidney cytosol CA or kidney brush border Mg(2+)-HCO3(-)-ATPase activities. In normal female rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the duodenal mucosa, and brush border Mg(2+)-HCO3(-)-ATPase activity in the kidney were increased by E.P. administration (100 and 500 micrograms/kg, daily for 7 days), however, kidney cytosol CA activity did not change by any dosage. Behavior of a part of both enzymes to E.P. in testectomized rats was altered almost in the same way to that observed in normal female rats and vice versa in ovariectomized rats. Body weight was decreased, in general, by consecutive administration of E.P. in a dose-dependent manner, and kidney weight was increased by E.P. in both male and female rats.

Peptidases in the kidney and urine of rats after castration

The localization of various peptidases in the renal section of the rat was investigated histochemically, and their activities were determined fluorometrically in renal homogenate. The membrane-bound peptidases aminopeptidase A (APA), aminopeptidase M (APM), gamma-glutamyl-transferase (gamma-GT), dipeptidylpeptidase IV (DAP IV), and the lysosomal dipeptidyl peptidases I (DAP I) and II (DAP II) were investigated in male and female (estrus) rats both before and 30 days after castration. In addition, protein excretion and APA, APM, DAP I and DAP IV activities were measured in the urine of these animals. Histochemically, the membrane-bound peptidases are demonstrable mainly in the brush borders of the proximal tubules. In addition, APA and DAP IV are found in the glomeruli, gamma-GT and DAP IV in the thin descending limbs of the loops of Henle, and gamma-GT in the basal labyrinth of the S2 and S3 segments. The lysosomal peptidases are most concentrated in the S1 and S2 segments of the proximal tubule, in the distal tubule, and in certain cells of the connecting tubule and collecting duct, where they are contained in lysosomes of varying size. Sex differences and castration effects are demonstrable both histochemically and biochemically for the investigated peptidases. Histochemically these effects are most pronounced in the S3 segments for the membrane-bound peptidases, and in the lysosomes of the proximal tubule for the lysosomal peptidases. Biochemical tests in controls show significantly higher lysosomal peptidase activities in the renal homogenate of females than of males. After castration the lysosomal peptidase activities in males increase, approaching those of females. This appears to have bearing on the sex-dependent proteinuria in rats, for lysosomal peptidases and proteinases are particularly important in the degradation of filtered proteins that are reabsorbed in the proximal tubule. In females high lysosomal peptidase activities correlate with a low proteinuria, while males demonstrate lower lysosomal peptidase activities and a significantly higher proteinuria than females. After castration, the lysosomal peptidase activities and proteinuria in males approach those in females. Renal peptidases are also excreted in the urine, again with sex differences, and so these excreted peptidases contribute to the proteinuria in rats.

[Distribution of some hydrolases in the rat kidney (author's transl)]

Most of the available histochemical methods and techniques (azodye, metal salt and indigogenic methods, cryostat, free-floating and lyophilized section techniques) and different modifications of these methods (different substrate concentrations, pH, temperature, incubation time e.g.) were applied to study the distribution of acid phosphatase (AcPB = after Barka and Anderson; AcPG = after Gomori), beta-glucuronidase (beta-Glu), aryl sulfatase (AS), beta-N-acetylglucosaminidase (NAG), acid 5'-nucleotidase (a5-Nucl), non-specific esterase (NE) and alkaline phosphatase (AlP) in the kidneys of rats of both sexes. The optimal conditions for the demonstration of these enzymes were established. As most important proved: the incubation of free-floating sections cut from "standard"-fixed (2 h in formol-calcium continued for another 18-22 h in the same fixative plus 0.88 M sucrose at 4 degrees C) kidney slices - only for AcPB and NE material fixed after Holt had to be used; the incubation for AlP and NE at 4 degrees C; final pH of the incubation medium for AcPB 5.5, AcPG 5.0 and NE 6.5; the use of Fast Garnet GBC Salt as coupler in the NE azo-dye reaction. Sex differences and for the female rats an increased activity during oestrus were established for all hydrolases studied. In particular the following results were obtained: AcPB, a5-Nucl and A1P are more intensive in male and AcPG in female S1 segments of the juxtamedullary nephrons in relation to the nephrons of the other parts of the cortex. In the medullary rays the NE and the a5-Nucl show a higher activity in the S2 segments of female rats demonstrate a more intensive activity for NAG and NE. This is true for AcPG and A1P in male rats. In the inner medulla a stronger beta-Glu activity in male rats and a stronger NAG activity in female rats is observed. The AcPB activity of the cortical distal tubules is higher in male rats.

Cytochemical correlates of structural sexual dimorphism in glandular tissues of the mouse

Circulating androgens are known to effect a sexual dimorphism of the submandibular gland and kidney of the mouse. Enzyme histocytochemical differences that correlate with these structural changes have been the subject of much study, especially in the kidney. In the present study, emphasis was placed on the hypogonadic effects of diabetes mellitus on the submandibular gland and kidney of C57Bl/KsJ db/db inbred mice with an autosomal recessive disease resembling maturity onset human diabetes mellitus. These glands of adult diabetic mice of both sexes were compared with those of unafflicted heterozygous littermates. The mitochondrial cytochrome oxidase and peroxisomal and cytoplasmic catalase were studied in their submandibular glands and kidneys. The parasympathetic innervation of the submandibular glands was studied by a histochemical method for acetylcholinesterase. The extensive differentiation of striated ducts of the submandibular gland into granular tubules in the postpubertal male mouse was readily evident with the cytochrome oxidase procedure. This differentiation resulted in ductal staining patterns characteristic of the sexes. Alteration of these patterns suggested that demasculinization or feminization was occuring in the male diabetic mice and that masculinization or virilization (defeminization) was occurring in the female diabetics. Similarly, in kidney, study of the parietal epithelium of Bowman's capsule revealed feminization in the male diabetics and masculinization in the female diabetics. With the catalase procedure, a dramatic sexual dimorphism was observed in the kidneys of the heterozygous unafflicted mice. Peroxisomal staining of epithelial cells of the proximal convoluted tubules was much more intense in the outer medulla of the male than of the female. In kidneys of the diabetics, the staining patterns again suggested that feminization of the male and masculinization of the female kidneys had occurred. On the other hand, neither a sexual dichotomy nor effects due to diabetes could be observed in the characteristic catalase staining observed in the luminal epithelial cells of submandibular gland distal ducts. The parasympathetic innervation of the submandibular gland, as revealed by the acetylcholinesterase method, was also markedly sexually dimorphic in the unafflicted mice. This was due to the more extensive innervation of the larger granular ducts characteristic of male than of the smaller striated ducts of the female. As a result of diabetes, the innervation and duct size decreased in the submandibular gland of the male, suggesting feminization, whereas they increased in the female suggesting masculinization. These changes were consistent with those observed in sumandibular gland with the cytochrome oxidase procedure. Attempts were made to interrelate all of the enzyme histochemical changes observed in submandibular gland and kidney with the weights of these glands, sex, gonadal weights, diabetic status and urinary protein excretion...

Histochemical, autoradiographic and electron microscopic investigations of the renal proximal tubule of male and female rats after castration

After castration of 90-day-old male and female rats, changes appear in the renal proximal tubule. A distinction can be made between early changes (up to 10th postoperative day) and later changes (20th-30th postoperative day). Between the 3rd and 5th day after castration the kidney of the females shows an increase in free estrogen receptors (biochemical studies) which are localized in the pars contorta of the proximal tubule (autoradiographic studies), while the male kidney shows a marked increase in urinary protein excretion up to the 10th day after castration. Proximal tubule changes detectable histochemically and electron microscopically do not appear until day 20 or 30 after castration. The results of castration are similar in segments S1 and S2. By days 20 and 30 after castration there is a decrease in the activity of lysosomal enzymes (acid phosphatase, acid beta-galactosidase). Electron microscopy shows a conspicuous decrease in the number of giant lysosomes (mainly in females) and apical vacuoles (mainly in males). A marked increase in the number of lysosomes is found in the S3 segment; females always have more lysosomes than males. The number of peroxisomes is also greatly increased; they appear circular in the females but can assume bizarre shapes in the males. Lipid droplets appear in the basal region of the tubule cell of segments S2 and S3 in the males. The sex differences are preserved in all segments even after castration and become even more pronounced in the S3 segment.

[Distribution of enzymes in the stereocilia of the ductus epididymis of rats (author's transl)]

Using unfixed or cryostate sections from aldehyde fixed epididymides of adult rats gamma-glutamyl naphthylamides are hydrolysed in the stereocilia of the principal cells in zone 1A-4B and glycyl-prolyl naphthylamides in those of zone 1B-4A (nomenclature of Reid and Cleland, 1957); this is not the case when other amino acid and peptide naphthylamides are employed. Adenosine triphosphate (ATP) is metabolized by the stereocilia in zone 1a, 2, 3 and 4A and adenosine monophosphate (AMP) in the stereocilia of zone 3-6. With thiamine pyrophosphate (TPP) especially the Golgi apparatus of the principal cells in zone 1B and C, 2 and 3 reacts. In addition ATP, AMP and TPP stain the stereocilia of single epithelial cells outside the zones where all stereocilia react. The AMP pattern allows a further subdivision of zone 3 into 3 A and B. Substrates for the demonstration of alpha- and beta-D-glycosidases, non-specific esterases and alkaline phosphatases are either not hydrolyzed by the stereocilia or the rate of hydrolysis is low.

[Histochemical and biochemical investigation of alpha-glucosidases by means of 2-naphthyl-alpha-D-glucoside (author's transl)]

Histochemical and biochemical studies yield the following method of choice for the in situ detection of neutral (microvillous) and acid (lysosomal) alpha-glucosidases: 12 mg 2-naphthyl-alpha-D-glucoside (dissolved in 0.5 ml N,N-dimethylformamide) and 0.6--0.8 ml hexazonium-p-rosaniline in 10 ml 0.1 M citric acid phosphate buffer for aqueous or 5 ml buffer mixed with equal parts of 2% agar for incubation with semipermeable membranes, pH 5 or 6.5. With this method neutral alpha-glucosidases can be exactly demonstrated in the brush border of the small intestine (glycoamylase, sucrase-isomaltase) and kidney of mammals, birds,fishes, amphibia and reptiles; localization of acid alpha-glucosidases is achieved at the cellular level in many organs and tissues. Fluorometric and photometric measurements prove that 2-naphthyl-alpha-D-glucoside is superior to 6-brom-2-naphthyl-alpha-D-glucoside for the demonstration of alpha-glucosidases in situ due to the lower Michaelis constant and higher maximal reaction velocity of the naphthol derivative.--Among the coupling reagents tested neutral alpha-glucosidases can be localized correctly with hexazotized p-rosaniline (with and without semipermeable membranes) for simultaneous coupling. Fast Blue B delivers false positive results in the suczedaneous and simultaneous coupling procedure using aqueous incubation media; in combination with the membrane technique azo dye can not be observed in the sections. Hexazonium-p-rosaniline inhibits neutral and acid alpha-glucosidases to nearly the same extent as Fast Blue B. Fixation of blocks of tissue in formaldehyde and glutaraldehyde suppresses alpha-glucosidases in the intestine and epididymis. The inhibition rates amount to 50 and 70% respectively. Washing in sugar solution rises enzyme activity to 65 and 50%. Species and organ dependent activity differences of neutral and acid alpha-glucosidases and changes of enzyme activity in the intestine and kidney after castration as well as in the course of pregnancy can be detected by means of biochemistry but not with the histochemical assay including minimal incubation. In comparison with p-nitrophenyl-alpha-D-glucoside the 2-naphthyl derivative is also the substrate of choice for the biochemical determination of alpha-glucosidases.--Agar gel electrophoresis reveals one band in the neutral and acid pH range.

Enzyme histochemistry as a link between biochemistry and morphology

The presented paper describes the role of enzyme histochemistry in cell biological investigations. In the first chapter a general discussion has been given about enzyme histochemistry as a connecting link between biochemistry and morphology. The methods available for determination of enzymes in a particular cell or cell compartment have been reviewed. In this respect the characteristics of enzyme histochemistry have been discussed. Furthermore, attention has been paid to the possibilities and limitations of enzyme histochemistry. In chapter two a comparison has been made between histochemically judged and biochemically determined enzyme activities. Some fundamental differences between the biochemical and the histochemical approach in cell biological investigations are dealt with. To correlate histochemically and biochemically determined enzyme activities, a description has been given of the application of histochemical methods on isolated fractions and sucrose-ficoll gradients of these fractions. Several experimental results are described concerning the question whether a relation exists between histochemically and biochemically determined activities of respectively alkaline phosphatase, glucose-6-phosphatase, 5'-nucleotidase and 3ss-hydroxysteroid dehydrogenase. From these results the conclusion could be drawn that in general a good correlation exists between histochemically judged activity per volume (area X thickness) and biochemically determined activity per gram tissue. In chapter three the role of enzymes as markers of cellular particles and as parameters of metabolic pathways is described. Histochemical methods are available for most marker enzymes. Only activities of key enzymes can be regarded as parameters of metabolic pathways. The distribution in sucrose-ficoll gradients of enzymes, regarded as markers of mitochondria, lysosomes, endoplasmic reticulum and plasma membranes has been given. The changes occur ing under different experimental conditions for a number of marker enzymes in rat liver are described. Attention has been given to the contibution of enzyme histochemistry in the study of the heterogeneity of mitochondria, the dual localization of some (lysosomal) enzymes, the complexity of the microsomal fraction, the function of the Golgi apparatus and the heterogeneity and function of plasma membranes. Based on these results and on literature findings the possible role of some marker enzymes in cell metabolism has been discussed. In chapter four problems coherent with species and sex differences in enzyme activities are described. The interpretation of histochemical and biochemical results in view of these differences is discussed. Enzymes characteristic for a given cell type -3ss-hydroxysteroid dehydrogenase in steroid producing cells, ATP-ase in liver plasma membrane surrounding the bile canaliculi - do show less variations between species and sexes than enzymes not directly involved in specialized functions...

Cytochemical correlates of structural sexual dimorphism in glandular tissues of the mouse. I. Studies of the renal glomerular capsule

The parietal epithelium of Bowman's capsule has been analyzed by enzyme cytochemistry in kidneys of mice (C57BL/6J) from birth to 50 days of age. There is a greater tendency for cells in the central portions of the capsular crescent to be cuboidal in post-pubertal males than in pre-pubertal mice of either sex or in post-pubertal females where they are generally squamous; moreover, these heightened capsular cells have a distinct microvillous border. Cytochemical procedures were selected which might confirm the morphological suggestion that the cuboidal parietal epithelium possesses an absorptive capacity. The oxidoreductase activity of the mitochondria of the cuboidal cells of this layer is comparable to that of the columnar cells of the proximal convoluted tubule. The cytochrome oxidase activity of the mitochondria in both of these segments of the nephron is intense. This is in sharp contrast to the unreactive mitochondria in the squamous cells of the parietal epithelium. Furthermore, a striking heterogeneity in the degree of cytochrome oxidase activity is evident in the mitochondria of the cuboidal parietal cells as well as in the cells of the proximal tubules. In the former cells, active mitochondria were generally found near microvilli at the apical ends and in the areas of the basal infoldings whereas those in a central position were more frequently unreactive. The brush border of the cuboidal capsular epithelium had prominent alkaline phosphatase and aminopeptidase activities as has previously been observed in other brush borders. Functional capacity corresponding to the morphological and cytochemical specialization of the cuboidal capsular cells was demonstrated by their uptake of horseradish peroxidase. This exogenous protein tracer could be seen in apical vacuoles and phagosomes in the cuboidal parietal epithelium. The cytochemical resemblance of the cells of this epithelium to those of the proximal convoluted tubules suggests a similar involvement in resorption and perhaps in active transport. A possible relationship of this differentiation of the capsular epithelium to the proteinuria normal for adult male mice is discussed.

[On the lysosomal pattern in the kidney of normal rats with special reference to the protein excretion(author's transl)]

Using the histochemical reaction for acid phosphatase the lysosomal pattern of the proximal renal tubule has been investigated in virginal female rats, in the course of pregnancy, and in females following pretreatment with progesterone. Furthermore the stage of gestation, phases of sexual cycle, the urinary output as well its protein concentration and the protein excretion have been taken into account. From the metabolic studies it becomes clear, that the urine values depend on the sexual phase and the duration of gravidity. On the basis of our histochemical results strong evidence occurs, that the lysosomes in the proximal renal tubule are influenced by both, the proteins in the primary urine and by sex hormones. In all collectives investigated an increase of the protein concentrations in the urine runs always parallel to an increase of the number of small and medium-sized lysosomes; the big ones disappear. At the end of pregnancy and after pretreatment with progesterone acid phosphatase seems to diffuse out of the lysosomes in the epithelial cells of the S1- and S2-segments.